For the purpose of renewing long track sections, the operations to be carried out are, as known, removal of the incoherent material interposed between the sleepers, typically crushed stones and gravel, and replacement of same with new material. This operation relies on known machines for ballast restoration or rehabilitation machines that, running at low speed on the track to be rehabilitated, continuously remove the crushed stones and gravel therefrom and discharge them into suitable trucks coupled up to the rehabilitation machine itself. Associated with each rehabilitation machine is a plurality of trucks, usually about twenty, forming a true train. Each truck for railroad rehabilitation machines of known type comprises a tank provided with wheels with rail gauge corresponding to the track to be rehabilitated. Installed on the tank bottom is a conveyor belt formed of mutually hinged rigid plates capable of supporting the weight of the debris gathered by the rehabilitation machine. The conveyor belt of the truck that is the closest to the rehabilitation machine receives the gravel and carries it, by means of the conveyor belt, to the subsequent truck so that the last truck in the row is filled the first and then all the other trucks in succession are filled. To carry out gravel discharge from a tank to another, each truck further comprises an auxiliary conveyor belt projecting in cantilevered fashion from the rear region of each tank. The auxiliary conveyor belt receives the gravel from the conveyor belt contained in the tank and lifts it until it lets the gravel fall into the subsequent truck.
Disadvantageously, the trucks of the above described type must be built to size, based on the gauge of the track to be rehabilitated. Therefore, each of the firms performing the rehabilitation operations referred to above must have at its disposal the same number of sets of trucks, each formed of about twenty elements, as the types of tracks on which each firm usually works. The cost of each truck that is already very high by itself because it also comprises the actuating unit of said truck defined by the bogies and possibly by a motor, multiplied by the number of the necessary trucks gives rise to a very high investment for the concerned firms.
In addition, due to the very high weight and bulkiness, the known trucks when not in use must be left on rented track sections the cost of which are to be added to those for purchase and servicing.
Finally, since the auxiliary conveyor belt keeps stationary and projects behind the last truck of the train, the presence of a safety railway truck is necessary which must be provided with the platform alone and coupled up behind the last truck for the rehabilitation machine. The safety truck prevents accidental impacts of other means running on rails, such as railway working machines or trains, against the projecting portion of the last truck for the rehabilitation machine. The presence of the safety truck makes the working times longer because, when the last truck is to be uncoupled from the fully loaded train it is also necessary to detach the safety truck and temporarily park it on an auxiliary track, to enable moving away of the filled truck.
Under this situation, the technical task underlying the present invention is to devise a tank for trucks of railroad rehabilitation machines, a truck for railroad rehabilitation machines and a process for making said truck which are able to obviate the mentioned drawbacks.
In particular it is an aim of the present invention to devise a tank for trucks of railroad rehabilitation machines that can be used on tracks with different gauges.
Another aim of the invention is also to propose a tank for trucks of railroad rehabilitation machines that can be stored in relatively reduced spaces and without involving renting and occupation of expensive track sections.
It is a further aim of the present invention to propose a tank for trucks of railroad rehabilitation machines that can also enable easy road transport, as well as transport by sea or by air.
Finally, it is an aim of the present invention to make available a truck for railroad rehabilitation machines and a method of making the same involving very reduced manufacturing and servicing costs as compared with those of the trucks of the known art.